MR2 Roadster Owners Club

The Workshop => Maintenance, Problems & Troubleshooting => Topic started by: tomato on February 3, 2024, 21:56

Title: O2 sensors
Post by: tomato on February 3, 2024, 21:56
I read a lot on forums about 02 sensors being a bit sensitive on the 2s.

Had the engine light come on earlier, plugged in the code machine and got 3 all linked to one sensor.

Codes 150, 153 and 174. Wiggled the wire a bit, checked for anything looking iffy, and then disconnected the battery, restarted the car, gone for a drive no engine light, no codes.

Are they just sensitive bunnies or is it on its way out, did not remove the sensor itself as they are as fragile as a bull in a china shop 🤔

Just wondering if should go get one and put it on the shelve ready to swap over, but no point if it likely to be a one off or an occasional issue.
Title: Re: O2 sensors
Post by: Joesson on February 3, 2024, 22:45
@tomato
Now in my 13th year of ownership of my 2002 2.
In the first year I removed the precats from the OE manifold. This was immediately followed by the demise of the RH (iirc) sensor.
This was replaced.
A year or so later the final  exit sensor died and was replaced.
So two are relatively new and one is OE.
Any replacement may stay on your shelf for some time. Why bother? Readily available and the car runs ( but not optimally) with one sensor out of order.
Title: Re: O2 sensors
Post by: Ardent on February 3, 2024, 23:37
What ^^^^ said
Title: Re: O2 sensors
Post by: tomato on February 4, 2024, 07:51
Thank you, i like that answer  :)
Title: Re: O2 sensors
Post by: Gaz mr-s on February 4, 2024, 11:44
It's more common for the heater cct to fail, but your codes are the sensor.  Often, it takes 3 engine cycles before the code notification returns.

Note it doesn't need to be an MR2 sensor.  Toyota-fit, using 4 wires with the thread mounting. (avoiding a clamping bracket type)  Measure the length of the cable & look at ads to see if it states cable length. The manifold sensors are short though, - I don't know if any use shorter cables than those.
Title: Re: O2 sensors
Post by: Carolyn on February 4, 2024, 11:51
Universal Densos with crimp connectors are a good way to go.  You really do want your sensors doing their job.
Title: Re: O2 sensors
Post by: McMr2 on February 4, 2024, 12:53
Bear in mind they can be a bit of a pig to remove if they've been in there for a while.

Edit: more specifically the post cat sensor (which I don't believe affects the fuelling in any way). Had to replace mine and ended up with the cat pipe on the bench, soaked in penetrating oil, using a proper socket and still needed a lot of encouragement.
Title: Re: O2 sensors
Post by: tomato on February 4, 2024, 14:10
We done 3 drives so far and its not returned.

As usual thanks for the advice, if keeps coming back will replace, hopefully not as troublesome as some has experienced 😁